U.S. patent number 4,656,900 [Application Number 06/798,518] was granted by the patent office on 1987-04-14 for rotary tube punching arrangement and method for punching holes into a moving web material.
This patent grant is currently assigned to Mobil Oil Corporation. Invention is credited to Fox J. Herrington.
United States Patent |
4,656,900 |
Herrington |
April 14, 1987 |
Rotary tube punching arrangement and method for punching holes into
a moving web material
Abstract
A method of accurately punching holes into a moving web of a
thermoplastic film material, and more particularly, punching holes
into the web through the intermediary of a rotary serrated tube
punch. The invention relates to accurately punching holes into an
advancing web of thermoplastic film material utilizing a novel
rotary serrated tube punch. The film web is continuously advanced
over at least a portion of the circumferential surface of a
rotatable anvil roll, and tensioned against the anvil roll surface
through the use of suitable tensioning devices, such as tension
rollers arranged upstream and downstream of the anvil roll. At
least one opening is formed in the circumferential surface of the
anvil roll which is slightly larger than the size of the hole which
is desired to be punched into the film web through the use of the
inventive rotary tube punching arrangement. The rotary tube punch
possesses a serrated cutting edge at its radially outermost end,
and is adapted to be rotated in synchronism with the anvil roll so
as to cause the serrated cutting edge pierce through the web in a
precisely aligned position with the opening in the rotating anvil
roll, and to thereby produce an accurately dimensioned hole in the
moving web without the necessity for stopping the web. The anvil
roll may be constructed hollow, and communicates with a suctioning
source for aspirating punched out film material segments.
Inventors: |
Herrington; Fox J. (Holcomb,
NY) |
Assignee: |
Mobil Oil Corporation (New
York, NY)
|
Family
ID: |
25173603 |
Appl.
No.: |
06/798,518 |
Filed: |
November 15, 1985 |
Current U.S.
Class: |
83/24; 83/100;
83/345; 83/37; 83/670 |
Current CPC
Class: |
B26D
7/1863 (20130101); B26F 1/10 (20130101); B26F
1/384 (20130101); Y10T 83/0515 (20150401); Y10T
83/207 (20150401); Y10T 83/9389 (20150401); Y10T
83/0453 (20150401); Y10T 83/4836 (20150401) |
Current International
Class: |
B26D
7/18 (20060101); B26F 1/38 (20060101); B26F
1/10 (20060101); B26F 1/02 (20060101); B26D
007/18 () |
Field of
Search: |
;83/24,37,100,345,670,98,22 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Yost; Frank T.
Attorney, Agent or Firm: McKillop; Alexander J. Gilman;
Michael G. Speciale; Charles J.
Claims
What is claimed is:
1. A rotary die punching arrangement for punching holes into a
continuously advancing thermoplastic film web, comprising:
(a) a rotatable anvil roll constituted of a closed-ended hollow
cylindrical drum having said film web extending in surface contact
with at least a portion of the circumference of said roll; at least
one punch-receiving opening of predetermined size being formed in
the circumferential surface of said hollow drum at a predetermined
location and having said film web advancing thereover, said opening
extending through the wall of said drum so as to communicate with
the hollow interior of said drum;
(b) a rotary punch having a serrated cutting edge at the radially
outer end thereof adapted to pierce said web and to enter said
opening in said anvil roll at predetermined intervals;
(c) means for rotating said rotary punch; and means for imparting
rotation to said anvil roll;
(d) means for synchronizing the rotational movements of said anvil
roll and said rotary punch said film web advancing over said
opening on the anvil roll facing said punch whereby said serrated
cutting edge punches a hole into said web upon entering said
opening in said anvil roll;
(e) and suctioning means communicating with the interior of said
hollow drum for aspirating thee segments of said film web punched
out by said rotary punch.
2. An arrangement as claimed in claimed in claim 1, wherein said
opening in said anvil roll is slightly larger than the diameter of
said punch.
3. An arrangement as claimed in claim 1, comprising a stationary
frame structure, said means for rotating said rotary punch being a
first shaft rotatably journaled on said frame structure; said means
for rotating said anvil roll being a second shaft rotatably
journaled on said frame structure; and said means for synchronizing
the rotational movements of said rotary punch and said anvil roll
including means operatively interconnecting said first and second
shafts.
4. An arrangement as claimed in claim 3, wherein said means
operatively interconnecting said first and second shaft comprises
interengaged driving gears fsatened to the ends of said shafts for
rotating said shafts at predetermined counter-rotating speed
ratios.
5. An arrangement as claimed in claim 1, comprising means for
tensioning said film web during the advance of said web along the
circumferential surface of said anvil roll.
6. An arrangement as claimed in claim 5, wherein said film web
tensioning means comprise first and second freely-rotatable
tensioning rollers, one said tensioning roller being positioned
upstream of said anvil roll and the other said tensioning roller
being positioned at the downstream side of said anvil roll, said
film web being entrained over said tensioning rollers during
advance thereof.
7. An arrangement as claimed in claim 6, wherein the circumferences
of said tensioning rollers are in surface-contact with said anvil
roll.
8. A method for punching holes into a continuously advancing
thermoplstic film web, comprising:
(a) advancing said film web over a rotatable anvil roll constituted
of a closed-ended hollow drum with said film web extending in
surface contact with least a portion of the circumference of said
roll; at least one punch-receiving opening of predetermined size
extending through the circumferential surface of said anvil roll so
as to communicate with the interior of said hollow drum;
(b) causing a rotary punch having a serrated cutting edge at the
radially outer end thereof to pierce said film web and to enter
said opening in said anvil roll at predetermined intervals;
(c) rotating said rotary punch; and concurrently rotating said
anvil roll;
(d) and synchronizing the rotational movements of said anvil roll
and said rotary punch said film web advancing over said opening on
the anvil roll facing said punch to cause said serrated cutting
edge to punch a hole into said web upon entering said opening said
anvil roll;
(e) and suctioning the interior of said hollow drum for aspirating
the segments of said film web punched out by said rotary punch.
9. A method as claimed in claim 8, wherein said opening in said
anvil roll is slightly larger than the diameter of said punch.
10. A method as claimed in claim 8, comprising rotating said rotary
punch with a first shaft rotatably journaled on a stationary frame
structure; rotating said anvil roll with a second shaft rotatably
journaled on said frame structure; and synchronizing the rotational
movements of said rotary punch and said anvil roll by operatively
interconnecting said first and second shafts.
11. A method as claimed in claim 10, comprising operatively
interconnecting said first and second shafts by interengaged
driving gears fastened to the ends of said shafts for rotating said
shafts at predetermined counter-rotating speed ratios.
12. A method as claimed in claim 8, comprising tensioning said film
web during the advance of said web along the circumferential
surface of said anvil roll.
13. A method as claimed in claim 12, comprising tensioning said
film web over first and second freely-rotatable tensioning rollers,
one said tensioning roller being positioned upstream of said anvil
roll and the other said tensioning roller being positioned at the
downstream side of said anvil roll, and entraining said film web
over said tensioning rollers during advance thereof.
14. A method as claimed in claim 13, comprising positioning said
tensioning rollers in surface-contact with said anvil roll.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of accurately punching
holes into a moving web of a thermoplastic film material, and more
particularly, punching holes into the web through the intermediary
of a rotary serrated tube punch. Moreover, the invention also
relates to accurately punching holes into an advancing web of
thermoplastic film material utilizing a novel rotary serrated tube
punch.
In the production of various types of articles which are basically
formed from a thermoplastic film material, such as polyethylene
film or the like; for instance, articles such as plastic bags
employed in supermarkets or plastic garbage disposal or trash bags,
it is frequently necessary to provide holes in a web of the
thermoplastic film material employed for the high-speed series
production of the bags, which must be punched through at a high
degree of accuracy with respect to the location of the holes in the
film web and repetitions in successive hole patterns. Thus, for
instance, with regard to plastic bags onto which tapes are to be
applied and which are used for closing trash bags in the manner of
a drawstring, and into which there must be provided holes in order
to afford a consumer access to the tape for closing the bags, the
inability of presently employed production equipment in providing
accurately positioned and dimensioned holes necessitates wider
border edges to be formed on the film web for the receipt of such
tapes, with the result of requiring greater amounts of plastic
material in the formation of the bags thereby rendering current
manufacturing methods less than optionally economical.
Thus, a need has arisen in industry for methods and apparatus for
accurately punching holes of various sizes and configurations
through webs of thermoplastic film material, in which the webs are
conveyed in a continuous mode between processing stations so as to
afford optimized production rates and extremely high degrees of
manufacturing accuracy, without the need to stop the continual
advance of the film web during the hole punching procedure.
Heretofore, one particular method of punching holes through
polyethylene film webs contemplated the use of hole punching
apparatus incorporating a tube forming a die punch having a cutting
edge consisting of serrations or sharpened teeth facing towards the
film. For example, a punching apparatus of that type is disclosed
in Adams, et al. U.S. Pat. No. 3,580,120. The serrated cutting edge
of the punch is then pressed through the film web while the latter
is in a stationary condition during the intermittent advance of the
web and with the web being supported externally of the die punch in
order to maintain the necessary tension on the film web. Thus, in
order to employ a serrated punch for punching holes into a film
web, it is necessary to either advance the web only intermittently
in order to prevent it from moving while the hole is being punched,
or to reciprocate the punch so as to match the web speed when the
latter is continually advanced, or to press the punch through the
moving web and, as a result, produce a relatively ragged and
inaccurate hole. Consequently, the prior art hole punching methods
and apparatus are either complex in construction and/or cumbersome
in use, and fail to provide the required accuracy in forming
punched holes in a continuously advancing web of thermoplastic film
material.
2. Discussion of the Prior Art
Although rotary film web or sheet material punching devices are
known in the technology, none of these devices are analogous to the
arrangement pursuant to the present invention and to implementing
the hole punching method as disclosed herein.
Stoop U.S. Pat. No. 3,680,419 discloses a rotary punch device in
which a hollow rotating punch has a projecting cutting edge which
is adapted to cut holes into a paper web advanced over an anvil
roll, and wherein the chips which are punched out of the paper web
aspirated through the punch by a vacuum. This prior art device,
however, fails to provide for tensioning a thermoplastic film web
about the circumference of an anvil roll and the punching of holes
therethrough by a serrated cutting edge on a punch analogous to
that of the present invention, and thus would not be capable of
providing the desired degree of accuracy in the punching of holes
into a continuously advancing web of a thermoplastic film
material.
Leroy U.S. Pat. No. 4,480,516 discloses a rotatable cutting device
contacting an anvil or counter roll over which a film web is
advanced by means of a cutter possessing a cutting edge for
severing the web into predetermined sections. This does not allow
for the formation of holes in an accurate manner analogous to that
afforded by the device and method pursuant to the present
device.
Finally, Helm U.S. Pat. No. 3,728,918 discloses a rotary panel
cutter through the intermediary of which sections are cut out of a
continuously advanced film web. However, there is no disclosure of
a serrated cutter engaging into an opening in an anvil roll to
punch accurately-sized holes into a film web analogous to that of
the present invention.
SUMMARY OF THE INVENTION
In essence, the present invention provides for a rotary serrated
tube punching arrangement, in which a film web of a thermoplastic
material is continuously advanced over at least a portion of the
circumferential surface of a rotatable anvil roll which, if
desired, may be hollow, and tensioned against the anvil roll
surface through the use of suitable tensioning devices, such as
tension rollers arranged upstream and downstream of the anvil roll.
At least one opening is formed in the circumferential surface of
the anvil roll which is slightly larger in size than the size of
the hole which is desired to be punched into the film web through
the use of the inventive rotary tube punching arrangement. A
rotatable rotary tube punch possessing a serrated cutting edge at
its radially outermost end, is adapted to be rotated in synchronism
with the anvil roll so as to cause the serrated cutting edge pierce
through the web in a precisely aligned position with the opening in
the rotating anvil roll, and to thereby produce an accurately
dimensioned hole in the moving web without the necessity for
stopping the web.
Furthermore, the speeds of rotation and diameters of the anvil roll
and of the rotating punch may be correlated with respect to each
other, wherein the circumference of the anvil roll about which the
film web is transported is essentially equal to the repeat length
of the hole locations which are to be punched through the film web,
or equal to an integral fraction or multiple thereof. The serrated
cutting edge of the punch, the latter of which may be mounted on a
rotatable disc or on the end of an arm journaled on a rotating
shaft, rotates at a speed such that the cutting edge of the punch
travels at the same linear speed of advance as the speed of the
hole in the circumference of the anvil roll. The hole in the anvil
roll is slightly larger than the size of the serrated cutting edge
of the punch, with the surface of the anvil roll surrounding the
hole supporting the film web, and thereby facilitating the accurate
punching through of the film web by the cutting edge of the punch
as the latter enters the hole in the anvil roll.
Pursuant to another aspect of the present invention, the serrated
cutting edge on the punch and the hole in the anvil roll need not
be necessary round in shape, but may be configured to punch holes
in the film web which are of various shapes; such as, for example,
elliptical, oval or even olygonally-shaped holes possessing
accurate dimensions.
Accordingly, it is an object of the present invention to provide a
unique rotary punching arrangement incorporating a rotary serrated
tube punch engaging into a slightly larger opening provided in a
rotatable anvil roll over the circumference of which there is
tensioned a continuously advancing web of thermoplastic film
material in order punch accurately-sized holes into the web without
any distortion of the holes or the web material.
A more specific object resides in the provision of a rotary
serrated tube punch which is rotated in synchronism with an anvil
roll over which a thermoplastic film web is tensioned for forming
accurately-sized and spaced holes in the film web.
Pursuant to another aspect of the invention, aspirating means is in
communication with the interior of the anvil roll, the latter of
which is of a hollow drum construction, for suctioning out the
segments of the thermoplastic film web punched out by the serrated
punch, and conveying the segments to waste receiving or disposal
means.
In accordance with still another object of the present invention,
it is an object to provide a novel method for accurately punching
holes into a continuously advancing thermoplastic film web
utilizing the unique rotary serrated tube punch and anvil roll
arrangements as described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference may now be had to the following detailed description of
exemplary embodiments of the rotary tube punching arrangement,
taken in conjunction with the accompanying drawings; in which:
FIG. 1 illustrates a schematic representation of an apparatus for
punching holes in a continuously advancing film of a thermoplastic
film web material;
FIG. 2 illustrates, partly in section, a side elevational view of
an apparatus for punching holes in a continuously advancing web of
a thermoplastic film material;
FIG. 3 illustrates a sectional view of the apparatus taken along
line 3--3 in FIG. 2;
FIG. 4 illustrates a sectional view taken along line 4--4 in FIG.
3;
FIG. 5 illustrates an elevational view of a modified embodiment of
the apparatus; and
FIG. 6 illustrates, in a reduced scale, a sectional view taken
along line 6--6 in FIG. 5.
DETAILED DESCRIPTION
Referring to FIG. 1 of the drawings, there is schematically
illustrated a rotary die punching arrangement 10 for punching holes
into a continuously advancing web W of a thermoplastic film
material, for example, such as polyethylene film which is utilized
in the production of plastic bags, trash disposal bags or the like.
The die punching arrangement 10 basically incorporates an anvil
roll 12, which in this embodiment is preferably but not necessarily
of a hollow drum-like construction, and which has a punch-receiving
opening 14 formed in its circumferential surface. A pair of
freely-rotatable tension rollers 16 and 18 are positioned
respectively one each upstream and downstream of the anvil roll 12,
preferably in surface contact therewith, along which there is
conducted the film web W such that the rollers 16, 18 form
tensioning guides for the web W as the web is being conducted over
the circumferential surface of the anvil roll 12, to maintain the
film thereon in a predetermined tensioned condition. The anvil roll
12 is rotated through a suitable drive in the direction of arrow A,
while concurrently therewith a die punch arrangement 20 is rotated
in the counter-rotatable direction of arrow B in predetermined
synchronism therewith. The die punch arrangement 20 includes a
rotatable shaft member 22 which may be driven in synchronism
therewith with the anvil roll 12 by being either geared or belted
therewith, as detailed in connection with FIGS. 2 to 6, and
incorporates a radially extending tubular die punch 24 which, at
its free end, has a serrated cutting edge 26 adapted to project
into the punch-receiving opening 14 in the circumference of the
anvil roll so as to cause the die punch 24 to punch a hole into the
film web W.
The tensioning of the film web W by the tensioning rollers 16, 18
will ensure that the hole which is punched therein by the rotatable
punch 24 is accurately dimensioned and not distorted by any
shifting of the film web on the anvil roll surface as it is being
punched.
Referring to the particular embodiment of a rotary die punching
arrangement 30 disclosed in FIGS. 2 through 4 of the drawings,
rotatably supported from a stationary frame structure 32 is a
hollow anvil roll 34, which may be a closed-ended drum constituted
of a suitable metal, such as steel or the like. Projecting
coaxially from one end of the anvil roll 34 is a shaft 36 which is
fixed thereto, which is rotatably journaled in suitable bearings 38
provided in the stationary frame structure 32, and which shaft
mounts a spur gear 40 at its free end 42. The circumferential
surface of the anvil roll 34 is provided with at least one through
opening of predetermined size for receiving a die punch cutter. A
rotary punching device 46 consists of an arm member 48 which, at
one end thereof, is fixedly clamped to a rotatable shaft 50 which
is journaled in the frame structure 32, and which extends in
parallel spaced relationship with the shaft 36. A spur gear 52
fastened to the other end of the shaft 50 is in driving
interengagement with the spur gear 40 such that both shafts 36, 50
may be counter-rotated in predetermined synchronism by a suitable
driving arrangement (not shown).
Fastened to the opposite free end of the arm member 48 of the
punching device 46, such as by a screw fastening 54, is an annular,
or sleeve-like cutter 56 having a serrated or toothed cutting edge
58 facing towards the circumferential surface of the anvil roll
34.
The relative rotational movement between the arm member 48 that and
of the anvil roll 34 is correlated and synchronized, for example,
by the ratio of the pitch diameters of the interengaged gears 40,
52; the radius of rotation of the cutter 56 about its shaft 50, and
the diameter of the anvil roll 34. This then will ensure that the
cutting edge 58 will enter the opening 60 formed in the
circumferential surface of the anvil roll 34 in an aligned,
accurate manner at predetermined intervals of rotation of the anvil
drum.
Thus, for example, in producing bags from the plastic film web W
which have a repeat length of 30 inches, the anvil roll 34 has a
circumferential length of 15 inches. The cutting edge 58 of the
cutter 56 has a radius of rotation of about 5 inches about its
shaft 52, such that the rotary punching device 46 makes one
revolution for every two revolutions of the anvil roll 34. As drawn
more clearly in FIG. 4, the cutter 56 is about 2 inches in
diameter, whereas the opening 60 in the anvil roll is about 21/8
inches in diameter, with the cutter imbedding about 9/16 inch into
the opening 60 when piercing through the film web W.
The holes need not be necessarily round, but may be oval or
elliptical as shown in FIG. 4 of the drawings, and the arrangement
is also adapted to punch accurately-sized holes in the film web W
possessing different configurations.
In the modified embodiment of the rotary die punching arrangement
70 of the invention pursuant to FIGS. 5 and 6, in which components
which are similar to or identical with those in the embodiment of
FIGS. 2 to 4 are designated by the same reference numerals, the
cutter 56 and its serrated cutting edge 58 are mounted on a
rotatable disc member 72 which is fastened to the rotatable shaft
52, in lieu of being mounted on an arm member 48.
In this embodiment, the interior of the anvil roll 34 incorporates
a passageway 74 which is in communication with the opening 60 and a
suctioning device (not shown) for aspirating the punched-out
portions of the film web W into the passageway 74, and then
discharging them through an outlet 76 for further processing or to
a waste disposal.
From the foregoing, it clearly appears that the invention is
directed to an extremely simple rotary die punching arrangement for
accurately punching holes through a continuously advancing film of
a thermoplastic web material, wherein the holes in the web may be
spaced as required depending upon the proportional diameters and
speeds of rotation of the anvil roll and the rotary die punch,
while concurrently permitting the punching of holes of
configurations which are other than round into the web.
While there has been shown and described what are considered to be
preferred embodiments of the invention, it will of course be
understood that various modifications and changes in form or detail
could readily be made without departing from the spirit of the
invention. It is therefore intended that the invention be not
limited to the exact form and detail herein shown and described,
nor to anything less than the whole of the invention herein
disclosed as hereinafter claimed.
* * * * *